$-5lm - 3ln + 4l - 8 = 5m + 1$ Solve for $l$.
Solution: Combine constant terms on the right. $-5lm - 3ln + 4l - {8} = 5m + {1}$ $-5lm - 3ln + 4l = 5m + {9}$ Notice that all the terms on the left-hand side of the equation have $l$ in them. $-5{l}m - 3{l}n + 4{l} = 5m + 9$ Factor out the $l$ ${l} \cdot \left( -5m - 3n + 4 \right) = 5m + 9$ Isolate the $l$ $l \cdot \left( -{5m - 3n + 4} \right) = 5m + 9$ $l = \dfrac{ 5m + 9 }{ -{5m - 3n + 4} }$